转载：http://blog.csdn.net/linxingliang/article/details/52069482
Web开发使用 Controller 基本上可以完成大部分需求，但是我们还可能会用到 Servlet、Filter、Listener、Interceptor 等等。
当使用spring-Boot时，嵌入式Servlet容器通过扫描注解的方式注册Servlet、Filter和Servlet规范的所有监听器（如HttpSessionListener监听器）。
Spring boot 的主 Servlet 为DispatcherServlet，其默认的url-pattern为“/”。也许我们在应用中还需要定义更多的Servlet，该如何使用SpringBoot来完成呢？
在spring boot中添加自己的Servlet有两种方法，代码注册Servlet和注解自动注册（Filter和Listener也是如此）。
一、代码注册通过ServletRegistrationBean、 FilterRegistrationBean 和ServletListenerRegistrationBean 获得控制。
也可以通过实现 ServletContextInitializer 接口直接注册。
二、在SpringBootApplication 上使用@ServletComponentScan注解后，Servlet、Filter、Listener 可以直接通过 @WebServlet、@WebFilter、@WebListener 注解自动注册，无需其他代码。
这里我们新建一个spring-boot-hello2java工程进行测试；这里不过多进行说明，如果这个还不会的话，请回到上上上一章进行查看。
通过代码注册Servlet示例代码：
package com.kfit.servlet;
import Java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
importjavax.servlet.http.HttpServletRequest;
importjavax.servlet.http.HttpServletResponse;
/**
*
* @author Angel(QQ:412887952)
* @version v.0.1
*/
//这个不需要添加.
//@WebServlet(urlPatterns="/myServlet1/*", description="Servlet的说明")
public class MyServlet1 extends HttpServlet{
private static final long serialVersionUID = 1L;
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throwsServletException, IOException {
System.out.println(">>>>>>>>>>doGet()<<<<<<<<<<<");
doPost(req, resp);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throwsServletException, IOException {
System.out.println(">>>>>>>>>>doPost()<<<<<<<<<<<");
resp.setContentType("text/html");
PrintWriter out = resp.getWriter();
out.println("<html>");
out.println("<head>");
out.println("<title>HelloWorld</title>");
out.println("</head>");
out.println("<body>");
out.println("<h1>这是：MyServlet1</h1>");
out.println("</body>");
out.println("</html>");
}
}
package com.kfit;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
importorg.springframework.boot.context.embedded.ServletRegistrationBean;
importorg.springframework.boot.web.servlet.ServletComponentScan;
import org.springframework.context.annotation.Bean;
import com.kfit.servlet.MyServlet1;
/**
*
*
* 大家也许会看到有些demo使用了3个注解：@Configuration；
*
*@EnableAutoConfiguration
* @ComponentScan
*
* 其实：@SpringBootApplication申明让spring boot自动给程序进行必要的配置，
*
* 等价于以默认属性使用@Configuration，
* @EnableAutoConfiguration和@ComponentScan
*
* 所以大家不要被一些文档误导了，让自己很迷茫了，希望本文章对您有所启发；
*
* @authorAngel(QQ:412887952)
* @version v.0.1
*/
@SpringBootApplication
public class App {
/**
* 注册Servlet.不需要添加注解：@ServletComponentScan
* @return
*/
@Bean
publicServletRegistrationBean MyServlet1(){
return newServletRegistrationBean(new MyServlet1(),"/myServlet/*");
}
public static voidmain(String[] args) {
SpringApplication.run(App.class,args);
}
}
右键Run As JavaApplication进行访问http://127.0.0.1:8080/myServlet1
使用注解注册Servlet示例代码
com.kfit.servlet.MyServlet2.java
package com.kfit.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
*
* @authorAngel(QQ:412887952)
* @version v.0.1
*/
@WebServlet(urlPatterns="/myServlet2/*",description="Servlet的说明")
public class MyServlet2 extends HttpServlet{
private static finallong serialVersionUID = 1L;
@Override
protected voiddoGet(HttpServletRequest req, HttpServletResponse resp) throwsServletException, IOException {
System.out.println(">>>>>>>>>>doGet()<<<<<<<<<<<");
doPost(req, resp);
}
@Override
protected voiddoPost(HttpServletRequest req, HttpServletResponse resp) throwsServletException, IOException {
System.out.println(">>>>>>>>>>doPost()<<<<<<<<<<<");
resp.setContentType("text/html");
PrintWriter out =resp.getWriter();
out.println("<html>");
out.println("<head>");
out.println("<title>Hello World</title>");
out.println("</head>");
out.println("<body>");
out.println("<h1>这是：myServlet2</h1>");
out.println("</body>");
out.println("</html>");
}
}
SpringBootSampleApplication.java
package com.kfit;
import org.springboot.sample.servlet.MyServlet;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.context.embedded.ServletRegistrationBean;
import org.springframework.boot.web.servlet.ServletComponentScan;
import org.springframework.context.annotation.Bean;
import org.springframework.web.servlet.DispatcherServlet;
@SpringBootApplication
@ServletComponentScan//这个就是扫描相应的Servlet包;
public class SpringBootSampleApplication {
public static void main(String[]args) {
SpringApplication.run(SpringBootSampleApplication.class, args);
}
}